The present invention relates to a stack of flexible sheet material and to a dispenser containing such stack. The stack contains a plurality of sheets with each sheet attached to the other by repositionable adhesive and wherein at least two sheets are different from each other. The present invention farther relates to a method for applying coating material to a plurality of sheets of which at least two sheets are different and to an apparatus for carrying out that method.
U.S. Pat. No. 5,417,345 discloses a dispensing device for use in dispensing sheets of material coated along one edge with a narrow band of readily releasable pressure-sensitive adhesive. The dispenser comprises a container having a pair of sidewalls connected by a top wall which is formed with a transversely extending rectangular opening extending in the direction parallel to the side walls. The sheets are stacked within the dispenser such that upon removing the uppermost sheet in the stack the adhesive coating along one edge of the sheet adhered to the edge of the next sheet in the stack will cause the next sheet in the stack to be withdrawn at that free edge through the dispensing opening upon withdrawal of the uppermost sheet. A typical embodiment disclosed includes a stack of sheets where the adhesive alternates between two opposite edges of the stack. Further, dispensers such as those disclosed in this patent are commercially available. However, a stack of sheets used therein typically consists of sheets that are all similar.
There exists now a desire to have one or more sheets in the stacks of such dispensers to be different from the other sheets in the stack. For example, it may be desirable to have sheets of alternating color in the stack or to have one or more sheets in the stack that contain a message, in particular an advertisement or an indication that the end of the stack is approaching.
It has however until now not been possible to produce such stacks of sheets where the adhesive alternates between opposite edges. In particular, a stack of sheets as disclosed in U.S. Pat. No. 5,417,345 is typically prepared by coating the adhesive stripes to a continuous web of sheet material, for example paper. Such process does not give the required flexibility needed to produce stacks in which one or more sheets are different from the other sheets.
WO 94/19419 discloses a process for coating a plurality of individual sheets with adhesive, for example repositionable adhesive. This process allows for one or more sheets, different from the other sheets to be inserted during the coating process thereby allowing to produce a stack of sheets with inserts. However, the process disclosed in this patent application is not adapted to produce stacks of sheets where the adhesive alternates between opposite edges of the stack and that can be used in a dispenser such as disclosed in the above U.S. Pat. No. 5,417,345.
The present invention provides a stack of flexible sheet material comprising a plurality of sheets disposed one on top of another, each sheet having repositionable adhesive along one edge and being free of adhesive along the opposite edge and the sheets are stacked with the repositionable adhesive edge of each sheet disposed along alternate opposite edges to maintain the sheets in the stack, characterised in that said stack comprises at least two sheets that are different from each other.
The present invention also provides a dispenser comprising a stack of sheets as defined above, said dispenser having wall means enclosing the stack including a top wall with a transverse opening through which a portion at the edge free of adhesive of the uppermost sheet in the stack extends.
The present invention further provides a method for applying coating material to sheets, comprising the steps of:
(a) applying coating material to an endless transfer surface;
(b) conveying a plurality of sheets, of which at least two sheets are different from each other, in an overlapped end-to-end relationship to a transfer location; and
(c) contacting the sheets at the transfer location with the transfer surface to transfer the coating material to the sheets thereby obtaining a coated area on each of said sheets;
wherein said coating material is applied to said endless transfer surface such that when coating material is transferred to a first and second sheet that are next to each other, the coated areas on said first and second sheets are offset relative to each other in the direction perpendicular to the direction of conveyance of the sheets.
Also provided is an apparatus for applying coating material to a plurality of sheets, the apparatus including a conveyor arrangement for conveying a plurality of sheets in overlapped end-to-end relationship to a transfer location;
an endless transfer surface which is movable through the transfer location in contact with the conveyed sheets;
and a coating means arranged to apply, to the endless transfer surface, coating material for subsequent transfer to sheets to form coated areas thereon at the transfer location;
wherein said coating means is capable of applying coating material to said endless transfer surface in such a way that when coating material is transferred to a first and second sheet that are next to each other, the coated areas on said first and second sheets are offset relative to each other in the direction perpendicular to the direction of conveyance of the sheets.